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Cross catalogue matching with VO and parameterization of stars

Cross catalogue matching with VO and parameterization of stars. Oleg Malkov , Olga Dluzhnevskaya , Sergey Karpov , Elena Kilpio , Aleksey Kniazev , Aleksey Mironov , Sergey Sichevskij Institute of Astronomy, Russ. Acad. Sci. Faculty of Physics, Moscow State University

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Cross catalogue matching with VO and parameterization of stars

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  1. Cross catalogue matching with VO and parameterization of stars Oleg Malkov, Olga Dluzhnevskaya, Sergey Karpov, Elena Kilpio, Aleksey Kniazev, Aleksey Mironov, Sergey Sichevskij Institute of Astronomy, Russ. Acad. Sci. Faculty of Physics, Moscow State University Special Astrophysical Observatory, Russ. Acad. Sci., South African Astronomical Observatory Sternberg Astronomical Institute, Moscow State University JENAM-2011, SpS3

  2. Outline • Parameterization of stars: extinction reddening and temperature reddening • Cross-correlation of multiwavelength catalogues: reliable results • Construction of color index diagrams: models – reddening – GALEX/SDSS observations • Binaries recognition on color index diagrams • Summary, future work JENAM-2011, SpS3

  3. Reddening on color index diagrams Extinction reddening U-B Temperature reddening B-V JENAM-2011, SpS3

  4. Extinction reddening and temperature reddening can be separated, when a significant deviation from monotonic function is observed • in stellar spectrum, e.g. • Balmer jump area for B5-G0 stars • molecular bands in the spectrum of M stars • in the Interstellar extinction law • extremely high extinction in a broad bump at about =2175 A JENAM-2011, SpS3

  5. Cross-matching: general problem • The aim is to reliably link the same object data in different catalogues • different sky coverage • different detection limits • different object densities • 2MASS — 50 objects • SDSS — 133 objects • UKIDSS — 176 objects • GALEX — 342 objects in l,b,r=(210°,12°,0.1°) area Which one is correct?.. JENAM-2011, SpS3

  6. Cross-matching:finding reliable matches • Positional match • all objects from one catalogue within given radius from each object of second catalogue • Parametric filtering • nearby bands = nearby magnitudes • similar objects = similar colors • Postfactum filtering • rejection of outliers after final spectral fitting JENAM-2011, SpS3

  7. Cross-matching:finding reliable matches Adequate match radius JENAM-2011, SpS3

  8. Cross-matching:technology • Extraction of data for selected fields • VO, Registries, ConeSearch, VOTable • Indexing to speed-up spatial queries • HTM — Hierarchical Triangular Mesh • Matching and filtering • Python + ATPy + NumPy • Visual checking • Topcat, Python + MatplotLib JENAM-2011, SpS3

  9. Outline • Parameterization of stars: extinction reddening and temperature reddening • Cross-correlation of multiwavelength catalogues: reliable results • Construction of color index diagrams: models – reddening – GALEX/SDSS observations • Binaries recognition on color index diagrams • Summary, future work JENAM-2011, SpS3

  10. Modelling: choice of spectral library • An analysis shows thatPickles A.J. (1998, Publ. Astron. Soc. Pac. 110, 863) is one of the best (semi)empirical libraries • Drawbacks: • LC are from I toV (no WDs), • Spectral type serves as an input parameter (usage of continuous parameters – Teff, lg g, … – is more comfortable) • Early type stars (O-B3) remain reddened JENAM-2011, SpS3

  11. Modelling: response curves and interstellar extinction law • Response curves of UV photometry surveys • SDSS (Gunn J.E. et al. 1998, AJ 116, 3040) • GALEX (Morrissey P. et al. 2005, ApJ 619, L7) • Fluks et al. (1994, AAS 105, 311) interstellar extinction law JENAM-2011, SpS3

  12. SDSS: theory and observations Filled black circles – Pickles (1998) models recalculated into the AB magnitude system Open black circles – the reddened (EB-V=1) models Red arrow – reddening curve Gray points – SDSS stars Outlined gray points – SDSS stars with photometric u,g,r accuracy better than 0.1 mag l=353º, b=+68º, r=0.1º (Boo) JENAM-2011, SpS3

  13. GALEX/SDSS: theory and observations l=353º, b=+68º, r=0.1º (Boo) l=228º, b=+27º, r=0.1º (Hya) Filled black circles – Pickles (1998) models recalculated into the AB magnitude system Open black circles – the reddened (EB-V=1) models Red arrow – reddening curve Blue squares – GALEX/SDSS stars JENAM-2011, SpS3

  14. Possible reasons for disagreement of observational and simulated points: • Observational error, misprint in catalogue or cross-matching error • The star is a variable • The star belongs to other LC • Non-stellar nature of the object (galaxy, …) • Non-standard interstellar extinction law in the area • ... • The star is a photometrically unresolved binary JENAM-2011, SpS3

  15. Outline • Parameterization of stars: extinction reddening and temperature reddening • Cross-correlation of multiwavelength catalogues: reliable results • Construction of color index diagrams: models – reddening – GALEX/SDSS observations • Binaries recognition on color index diagrams • Summary, future work JENAM-2011, SpS3

  16. Unresolved binaries simulation • Some photometrically unresolved binaries exhibit colors different enough from ones of single stars. • Such binaries can be separated from single stars in some color index diagrams. • The goal is to specify those binaries and those color index diagrams. JENAM-2011, SpS3

  17. The following pairs can be unfiled: • Evolutionary meaningless pairs. • Pairs with components of very different luminosity (m>3m). • Pairs with components of similar temperature(Sp<½ Sp, it approximately giveslog Teff = 0.1 for hot stars, and 0.02 for cool stars). However, such pairs are recognizable on color-magnitude plots, as they have an increased luminosity for a given color. JENAM-2011, SpS3

  18. An example:GALEX/SDSS colors of A0V+K0III unresolved binary A0V+K0III binary, components have approximately equal masses, around 2-2.5 mo Extinction reddening curves. The observed colors can be significantly distorted due to extinction. Supergiant, giant and main sequence single stars Here interstellar extinction does not prevent to discover the pair. The binary, even being reddened, is separated from single stars. JENAM-2011, SpS3 Note the different axis scale

  19. A0V+K0III GALEX/SDSS photometry, three-color diagrams JENAM-2011, SpS3

  20. Summary • Method for reliable cross-matching of catalogues with different object densities is realized • A tool for simulation of color index diagrams is constructed. • It is shown that GALEX/SDSS photometry can be used for [even reddened] single-binary star separation and for parameterization of stars. JENAM-2011, SpS3

  21. Future work • Cross-matching of current surveys (GALEX, SDSS; together with UKIDSS, DENIS, 2MASS photometry) and use of coming data (Gaia, WSO-UV, Lira-B, Svecha). • Parameterization of single and, when possible, binary stars. • Determination of extinction value in a given area, and construction of a 3D galactic interstellar extinction map. JENAM-2011, SpS3

  22. Acknowledgements • We thank Marina Lobanova for collaborationand valuable comments. • This work has been supported • byRussian Foundation for Fundamental Research grants09-02-00520, 10-02-00426 and10-07-00342, • by the Federal Science and Innovations Agencyunder contract 02.740.11.0247, • by the Federal target-oriented program "Scientific and pedagogical stafffor innovation Russia" under contract P1195 • by the Presidium RAS program “Leading Scientific Schools Support‘” 4354.2008.2. JENAM-2011, SpS3

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